package en.edu.scau.cmi.zhanzhiyong.carpter09;

import java.util.Scanner;

public class Example9_9 {
	public static void main(String args[]) {
		String regx = "[a-zA-Z]+";
		
		Scanner scanner = new Scanner(System.in);
		
		String str = scanner.nextLine();
		
		if(str.matches(regx)) {
			System.out.println(str);
		}
	}
}
